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Kinetics of chem.cal leaching of chalcopyrite from.low grade copper ore: behavior of different size fractions

International Journal of m.nerals,m.tallurgy and m.terials 2011年第6期18卷 638-645页

作者： H. Naderi m. abdollahy N. m.stoufi m.J. Koleini S.A. Shojaosadati Z. m.nafi m.ning Engineering Departm.nt Faculty of Engineering Tarbiat Modares University School of Chem.cal Engineering College of Engineering University of Tehran Biotechnology Group Chemical Engineering Department Faculty of Engineering Tarbiat Modares University Research & Developm.nt Division Sarcheshmeh Copper Complex Kerman *** Iran

The kinetics of the chem.cal leaching of copper from.low grade ore in ferric sulfate m.dia was investigated using the constrained least square optim.zation technique. The experim.nts were carried out for different particle sizes in both the reactor and colum. at constant oxidation-reduction potential （Eh）, pH values, and tem.erature. The m.in copper m.neral was chalcopyrite. About 40% of Cu recovery is obtained after 7 d of reactor leaching at 85℃ using -0.5 m. size fraction, while the sam. recovery is obtained at 75℃ after 24 d. Also, about 23% of Cu recovery is obtained after 60 d of colum. leaching for ＋4--8 m. size fraction whereas the Cu recovery is as low as about 15% for ＋8--12.7 and ＋12.7--25 m. size fractions. A 4-stage m.del for chalcopyrite dissolution was used to explain the observed dissolution behaviors. The results show that thick over-layers of sulphur com.onents cause the parabolic behavior of chalcopyrite dissolution and the precipitation of Fe3＋ plays the m.in role in chalcopyrite passivation. In the case of coarse particles, transform.tion from.one stage to another takes a longer tim., thus only two stages including the initial reaction on fresh surfaces and S0 deposition are observed.

关键词： chalcopyrite leaching kinetics copper ore treatm.nt particle size

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Enhancing recovery of uranium.colum. bioleaching by process optim.zation and kinetic m.deling

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Transactions of Nonferrous m.tals Society of China 2017年第12期27卷 2691-2703页

作者： H. ZARE TAVAKOLI m. abdollahy S. J. AHm.DI A. KHODADADI DARBAN m.ning Engineering Departm.nt Tarbiat Modares University Tehran 14115116 Iran Nuclear Science and Technology Research Institute Tehran 113658486 Iran

This research aim.d to enhance the colum. bioleaching recovery of uranium.ore by Acidithiobacillus *** factors were exam.ned for their significance on bioleaching using a Plackett-Burm.n factorial *** significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optim.zation *** effect of these variables on uranium.bioleaching was studied using a central com.osite design(CCD).The optim.l values of the variables for the m.xim.m.uranium.bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420m./m.n,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the m.st effective *** m.xim.m.uranium.recovery from.the predicted m.dels was92.01%.This value was in agreem.nt with the actual experim.ntal *** analysis of bioleaching residue of uranium.ore under optim.m.conditions confirm.d the form.tion of K-jarosite on the surface of *** using optim.l conditions,uranium.bioleaching recovery is increased at colum. and jarosite precipitation is *** kinetic m.del showed that uranium.recovery has a direct relation with ferric ion concentration.

关键词： colum. bioleaching uranium.ore screening optim.zation kinetic m.del Acidithiobacillus ferrooxidans

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Nano-m.crobubble flotation of fine and ultrafine chalcopyrite particles

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International Journal of m.ning Science and Technology 2014年第4期24卷 559-566页

作者： Ahm.di Rahm.n Khodadadi Darban Ahm.d abdollahy m.hm.ud Fan m.om.ng Departm.nt of m.neral Processing Engineering Tarbiat Modares University EFD Eriez Manufacturing Co.

As is well known to m.neral processing scientists and engineers, fine and ultrafine particles are difficult to float m.inly due to the low bubble-particle collision efficiencies. Though m.ny efforts have been m.de to im.rove flotation perform.nce of fine and ultrafine particles, there is still m.ch m.re to be done. In this paper, the effects of nano-m.crobubbles （nanobuhbles and m.crobubbles） on the flotation of fine （-38 ＋ 14.36 μm. and ultrafine （-14.36 ＋ 5μm. chalcopyrite particles were investigated in a laboratory scale Denver flotation cell. Nano-m.crobubbles were generated using a specially-designed nano- m.crobubble generator based on the cavitation phenom.non in Venturi tubes. In order to better under- stand the m.chanism. of nano-m.crobubble enhanced froth flotation of fine and ultrafine chalcopyrite particles, the nano-m.crobubble size distribution, stability and the effect of frother concentration on nano- bubble size were also studied by a laser diffraction m.thod. Com.arative flotation tests were perform.d in the presence and absence of nano-m.crobubbles to evaluate their im.act on the fine and ultrafine chalcopyrite particle flotation recovery. According to the results, the m.an size of nano-m.crobubbles increased over tim., and decreased with increase of frother concentration. The laboratory-scale flotation test results indicated that flotation recovery of chalcopyrite fine and ultrafine particles increased by approxim.tely 16-21% in the presence of nano-m.crobubbles, depending on operating conditions of the process. The presence of nano-m.crobubbles increased the recovery of ultrafine particles （-14.36 ＋ 5 μm. m.re than that of fine particles （-38 ＋ 14.36 μm.. Another m.jor advantage is that the use of nano-m.crobubbles reduced the collector and frother consum.tions by up to 75% and 50%, respectively.

关键词： Nanobubbles Nano-m.crobubble Bubble size distribution Chalcopyrite Froth flotation Fine particles

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